1. Technical Field
This invention relates to microwave turntables and, more particularly, to an independently actuated turntable assembly for use with a microwave cooking device having an access door provided with a planar front edge registered along a front face of the microwave.
2. Prior Art
Portable turntables for microwave ovens are known and are commonly available in consumer markets. Such devices typically comprise a stationary base, a rotatable platform mounted to the base, and a drive motor. An on/off switching mechanism is generally provided to control the rotational movement of the platform relative to the base. Achievement of a suitable on/off switch for microwave turntables has proven illusive. Such switching mechanisms must be convenient to operate, fail-safe, and compact in spatial dimension so as to fit within the smaller microwave oven cavities. Further, the switching mechanism must smoothly act to move the turntable in and out of its rotational mode of operation without requiring manual manipulation.
While the above switch mechanism works well, it has certain deficiencies which prevent it from achieving all of the above-discussed performance requirements. First, operation of a sliding switch is cumbersome and can result in the turntable being pushed or pulled in jarring fashion. Undesired spillage of food stuffs supported by the turntable can result. Further, sliding actuation can cause the tooth of the sliding mechanism to stub against the gear teeth along the rim flange. Overcoming the impasse would require manual jogging of the lock mechanism and/or the turntable platform. However, such a procedure in the small confines of a microwave oven is awkward and can, again, result in foodstuff spillage.
One prior art example shows a switch assembly for a microwave oven turntable that comprises a base and a platform rotatably mounted thereupon. The platform is adapted having a downward peripheral rim flange, along which an annular gear ring is provided. A flange extends outward from the base beyond and below the rim flange. A switch mechanism includes a rocker body pivotally mounted to the flange and adapted to pivot toward and away from the flange. A locking finger extends under the rim flange and upward into a parallel and adjacent relationship with the gear ring.
The locking finger is of triangular saw-toothed cross section defining an apex ridge oriented toward the gear ring. The gear teeth of the gear ring likewise have a saw-tooth configuration. Rocking actuation of the switch body causes the locking finger to pivot toward and away from meshing engagement with the gear ring. Unfortunately, this prior art example requires manual operation of the switch mechanism wherein such a mechanism can be broken or damaged, thus rendering the invention useless for its intended purpose. In addition, this example does not provide a means of automatically returning the turntable to its starting position when cooking operations are completed.
One prior art example shows a two level turntable adapted for use in a microwave oven. The top level platform which may include a roasting rack is removably supported above the bottom level by a plurality of columns. The bottom level platform has a shaft that extends downwardly through an aperture in a microwave shielding enclosure to a motor. The motor components consisting of a coil spring and a braking mechanism are mounted in substantially the same horizontal plane to provide a relatively low vertical profile.
Although the low profile is important when the bottom level platform is used by itself, it is even more important when the top level platform is mounted on top. The shielding enclosure which includes a pan shaped bottom has a downwardly bent lip from the lid to provide a low microwave field region adjacent to the connection of the pan and lid. Unfortunately, this prior art example is cumbersome and occupies a large amount of interior space of a microwave while in use. In addition, this example also does not provide a means of automatically returning the turntable to its starting position when cooking operations are completed.
Accordingly, a need remains for an automated microwave turntable in order to overcome the above-noted shortcomings. The present invention satisfies such a need by providing a device that is convenient and easy to use, is lightweight yet durable in design, and assists a user to prepare food in a microwave cooking device. Such a device conveniently offers an automatic reference point whereby an item placed on the turntable advantageously returns to the original starting point when cooking operations are complete. The device effectively eliminates the risk of burns to a user from manually turning a cup or tray around in order to remove it from the microwave, and thereby increases the safety of use for adults and children. The device is available for use in private homes as well as businesses and commercial entities. The present invention is inexpensive, simple to use, and designed for many years of repeated use.